Create a .PHP file that creates .FIT file (Garmin workout sport file)

I need someone that creates a PHP file (one or several files) that is able to create a .FIT file (Garmin workout sport file). So .FIT files contains a workout (sport) to do while you run, bike or swim. For example, the workout inside the .FIT file could be: RUN for 10 minutes at 5min/km and then run for 20 min at 6 min/km and then "cool down" for 20 min The idea, is that I call this PHP file thet I need you to create, with a platform I already have. I send it GET or POST parameters with the workout. Then, the PHP creates the .FIT file, and ask the user download it. I have found some information about .FIT files, but I am unable to create them. This is what I have found: [login to view URL] [login to view URL] [login to view URL]